From the MakeUseOf site, here's a list of portable applications you use on your Eee PC (Windows version).

Note: Per the site, a portable app is one you can carry around with you on a portable device (e.g. USB flash drive) and use on any other computer. It can be your email program, your browser, system recovery tools or even an operating system. The coolest part about it, is that all of your data and settings are always stored on, say your USB drive, so when you unplug it, none of your personal data is left behind.

Among the apps listed (with their respective download links) are:

1. Portable Office Software
2. Portable Email/Calendar/ToDo Programs
3. Portable Text and Voice Messengers
4. Portable Media Tools (Audio / Video)
5. Portable Graphics Viewers and Image Editors
6. Portable Browsers and Web Tools (FTP, Feedreaders, Torrent clients…)
7. Portable Security Software
8. Portable Games
9. Other Portable Utilities
10. Portable Developer Tools (Techies Only)
11. All-In-One Packages
12. Portable Operating Systems (’HowTo’ Articles)
13. USB ThumDrive Tips

There are also download links for how-to articles as well as tutorial on various operating systems.

Check out the site - it definitely is worth your while.